1. Field of the Invention
The present invention relates to amphibious tracked craft having a frame connecting two spaced apart pontoons, a transom and an improved supplemental drive system that employs a hydraulically driven propeller, a universal joint connection to the transom, a hydraulic motor with in line drive and improved tilt and steerage.
2. General Background of the Invention
Amphibious marsh craft can be seen in the following US patents issued to John B. Coast, each of which is hereby incorporated herein by reference: U.S. Pat. Nos. 4,433,634; 4,961,395; 5,899,164; 6,234,260 and 6,305,882. In the past, such amphibious craft propel themselves across streams, lakes or other water bodies by simply running their tracks. Such craft have limited swimming capability using the tracks to propel in the water. Lightly loaded machines that float high in the water (e.g., with the centerline of the rear drive sprockets above the waterline) are capable of “swimming” at low speeds (e.g., approximately 2 mph). This capability allows these amphibious machines to cross canals, rivers, creeks, bayous, lakes, bays, etc., provided that wind and currents are low. One of the utilities of such amphibious craft is to carry heavy equipment such as seismic equipment or auger installing equipment. When the load on the machines increases, the rear of the machine and the rear sprocket centerline can dip below the waterline. The swimming capability with tracks only propelling then decreases to near zero.
In the prior art, some amphibious craft have provided a transom on the rear designed to accept an outboard motor. Outboards up to 40 horsepower (hp) have been used to propel these amphibious machines at speeds of over 3 mph. Outboard motors have thus given such machines good propulsion and maneuverability. However, this capability is rarely used because operators typically do not want to bother with handling the outboard motors and/or the gasoline tanks or fuel tanks required. Outboard motors are typically heavy four stroke units weighing two hundred pounds ore more (e.g., 40 horsepower Honda outboard weighs 214 pounds).